There are 4 tameable creatures with this look.
<The Accuser's Pet>
|Halls of Atonement, Revendreth|
|Patrols the southern perimeter.|
|Lurking Monitors phase out completely once you adjust the Scorching Mirror during the quest Securing Sinfall. They initially look like statues. You have to aggro one to reveal which colour it is. Note that they don't appear on your beast tracker until aggroed.|
|60||Stonevigil Overlook, Revendreth|
|Dominance Keep, Revendreth|
|Also found in the Ember Ward, just south of Dominance Keep.|